Apparatus for inductively heating an elongated workpiece

ABSTRACT

An apparatus for inductively heating an elongated workpiece preparatory to quench hardening, employing means for conveying the workpiece along a path, a single turn inductor positioned adjacent this path for inductively heating the elongated workpiece, as a unit, while it is being rotated, means for shifting the induction heating means away from the workpiece to clear the workpiece for movement along the path, and means for subsequently quench hardening the workpiece.

United States Patent Seyfried et al.

[ 51 Mar. 14, 1972 [54] APPARATUS FOR INDUCTIVELY 2,293,534 8/1942Denneen et al. ..266I4 E HEATING AN ELONGATED 5,243,883 311344 Degsgenet al. E K E l9,6l 4 l 47 w WOR PIEC 2,676,242 4/1954 Witsenburg [72]Inventors: Richard F. Seylried, Parma Heights; Nor- 2,787,566 4/1957Seulen et al.... bert R. Balzer, Parma, both of Ohio 3,240,480 3/1966Cary [73] Assigneez hrbohlo Industries, Inc Cleveland 3,494,604 2/ I970Remke et al. ..266I4 E Ohm Primary Examiner-Gerald A. Dost [22] Filed:Dec. 12, 1969 Attorney-Meyer, 'Iilberry and Body 211 Appl. No.: 884,49257] ABSTRACT An apparatus for inductively heating an elongated workpieceUS. Cl ..266l4 preparatory to quench hardening, employing means for comveying the workpiece along a path, a single turn inductor posi- [58]Sarch I tioned adjacent this path for inductively heating the elongatedworkpiece, as a unit, while it is being rotated, means for shifting theinduction heating means away from the workpiece to [56} Refe cued clearthe workpiece for movement along the path, and means UNITED STATESPATENTS for subsequently quench hardening the workpiece. 2,190,931 2/1940 Campbell ..266/4 S 5 Claims, ll Drawing Figures I nc PATENIEDMAR 141972 3. 648.995

sum 2 {1F 4 INVENTORS RICHARD F. SEYFRIED NORBERT R. BALZER BY M 744%,M04,

ATTORNEYS FIG. 2

IMENIEDMAH l4 i972 SHEEI 3 UF 4 ATTORNEYS FATENYEBMAR 14 I973 3, 648,9535 sum u 0F 4 INVENTORS (UNLOAD) RICHARD F. SEYFRIED NORBERT R. BALZERBY Maya, hum/u; 880d;

ATTORNEYS APPARATUS FOR INDUCTIVELY HEATING AN ELONGATED WORKPIECE Theinvention relates to the art of induction heating and more particularlyto an apparatus for inductively heating an elongated workpiecepreparatory to quench hardening.

This invention is particularly applicable for inductively heating andthen quench hardening axle shafts having a flange at one end, and itwill be described with particular reference thereto; however, it shouldbe appreciated that the invention has much broader applications and maybe used for other elongated workpieces, such as axle shafts withoutflanges.

It has now become somewhat common practice to quench harden the outersurface of an elongated axle shaft for increasing its torque carryingcapacity. A variety of apparatus has been developed for this purpose;however, the most commonly used apparatus includes means for rotatingthe axle shaft about a vertical axis, an inductor surrounding the axleshaft and movable progressively upwardly to heat the total length of theaxle shaft, and a quenching body surrounding the axle shaft forquenching the previously heated surface immediately after the heatingoperation. This equipment has operated quite satisfactorily and producesa uniformly hardened axle shaft. It has been found that this type ofapparatus does present some limitations on the production rate ofheating successive axle shafts. Each heating station must beindividually loaded and unloaded during which time there is no heatingand quenching taking place. Also, the heating cycle is determined by thelength of time necessary for the inductor and quench body to progressthe total length of the portion of the axle shaft being hardened. Thiscan be a substantial time according to the length of the axle shaft andthe rate at which the inductor is moved.

The present invention is directed toward an apparatus for heating andquench hardening an elongated workpiece, such as an axle shaft, whichovercomes the disadvantages experienced when employing the previous,most common axle shaft hardening apparatus by substantially increasingthe production rate of the apparatus.

In accordance with the present invention, there is provided an apparatusfor inductively heating and quench hardening an elongated workpiecehaving spaced ends and an elongated generally cylindrical body with alongitudinally extending axis. This apparatus comprises conveyor meansfor conveying the workpiece along a path generally transverse to theaxis; means for stopping movement of the workpiece when it reaches aselected position in the path and heating means at this selectedposition for inductively heating the cylindrical body. This heatingmeans comprises an inductor having a single turn conductor with twogenerally parallel side legs extending generally parallel to the axisand spaced slightly from the elongated body when the workpiece is at theselected position and end legs electrically connecting the side legs.The side legs extend generally the complete length of the cylindricalbody to be heated. There is also provided means for rotating theworkpiece about the axis while at the selected position, and means forcreating a high frequency current to flow through the conductor to heatthe body. The inductor has a first heating position with the side legsclosely adjacent the body and extending into the path of movement of theworkpiece and a second retracted position with the side legs spaced fromthe path of movement of the workpiece; means for shifting the inductorinto the retracted position as the conveyor means causes the workpieceto approach and depart from the selected position; means for shiftingthe inductor into the heating position when the workpiece is located inthe selected position by the stopping means; and, means for quenchingthe workpiece after it is inductively heated by the heating means.

By constructing the heating and quenching apparatus in the above-definedmanner, the heating and quenching can be accomplished on a conveyormeans wherein the loading and unloading takes place at the same time asthe heating and quenching operations. In this manner, a succession ofworkpieces, such as axle shafts, can be heated and quench hardenedwithout necessitating a time delay for loading and unloading workpiecesfrom the apparatus.

The primary object of the present invention is the provision of anapparatus for inductively heating and quench hardening a succession ofelongated workpieces, which apparatus reduces the total cycle time foreach workpiece.

Another object of the present invention is the provision of an apparatusfor inductively heating and quench hardening a succession of elongatedworkpieces, which apparatus uses a single turn inductor extending thelength of the workpiece and shiftable from the workpiece, as theworkpiece is moved to and from the inductor along a given path ofmovement.

Yet another object of the present invention is the provision of anapparatus for inductively heating and quench hardening a succession ofelongated workpieces, which apparatus has a production rate dependentupon only the longest of successive operations, instead of the total ofthe time for these successive operations.

Still a further object of the present invention is the provision of anapparatus for inductively heating and quench hardening a succession ofelongated workpieces, which apparatus moves the workpieces in a pathfrom a loading position, to a heating position, to a quenching position,and then to an unloading position on a single mechanism withoutreleasing the workpieces therefrom.

These and other objects and advantages will become apparent from thefollowing description taken together with the accompanying drawings inwhich:

FIG. 1 is a top view illustrating, somewhat schematically, the preferredembodiment of the present invention;

FIG. 2 is an enlarged cross-sectional view taken generally along line2-2 of FIG. 1;

FIG. 3 is a cross-sectional view illustrating the clamping deviceutilized in connection with the preferred embodiment of the presentinvention;

FIG. 4 is an enlarged partial view showing, schematically, the workpieceand inductor contemplated by the present invention;

FIG. 5 is an enlarged cross-sectional view taken generally along line5-5 of FIG. 4;

FIG. 6 is an enlarged partial view illustrating, schematically, anotheraspect of the preferred embodiment of the present invention;

FIG. 7 is an enlarged partial cross-sectional view illustrating,schematically, still another feature of the preferred embodiment of thepresent invention;

FIG. 8 is an enlarged partial view illustrating, schematically, a slightmodification of the structure illustrated in FIG. 4; and,

FIGS. 9-11 are schematic views showing other embodiments of the presentinvention.

Referring now to the drawings wherein the showings are for the purposeof illustrating a preferred embodiment of the invention only, and notfor the purpose of limiting same, FIGS. I and 2 show an inductionheating and quench hardening apparatus A for hardening the outercylindrical surface of a workpiece, illustrated as a flanged axle shaftB. In accordance with the illustrated embodiment of apparatus A, thereis provided a conveying and workpiece engaging mechanism, in the form ofa turret It), for moving successive workpieces B betweencircumferentially spaced positions, identified as I, II, III, and IV inFIG. 2. Of course, various other types of conveying and work engagingmechanisms could be used without departing from the intended scope ofthe present invention. At position I there is provided a loading device12 for loading a workpiece B onto the turret 10. After the turret hasbeen indexed, this workpiece is advanced to position II where there isprovided an induction heating device I4 which forms an essential aspectof the present invention and will be described in detail later. Turret10 then moves the workpiece B to position III where there is provided aquenching device I6 which forms another aspect of the present inventionand will be described in more detail later. As the turret I0 is againindexed, the workpiece B is moved to position IV where there is providedan unloading device 18 and an auxiliary quenching device 20. Belowposition IV a quench tank 22 receives the workpieces from the unloadingdevice and an inclined conveyor 24 in this tank removes the workpiecesfrom the apparatus A.

In the illustrated embodiment of the present invention, the workpiece Btakes the form as shown in FIG. 4 and includes spaced ends 30, 32connected by a generally cylindrical body 34. At end 30 there is acommonly used splined portion 36, and at end 32 there is a somewhatcommonly used flanged 38. It is appreciated that this workpiece may takea variety of forms other than the illustrated form shown in FIG. 4.

As so far explained, a workpiece B is loaded onto turret I at position Iby the loading device I2. Thereafter, the turret is indexed to bring theworkpiece into position I] where it is inductively heated, while beingrotated in a manner to be described. At the same time, another workpieceis being loaded onto the turret 10 by device I2. Turret I0 is againindexed, approximately 90, which brings the first-mentioned workpiece Binto position III wherein the quenching device I6 quench hardens theheated workpiece to provide the proper hardness on the surface of theworkpiece. At this time, another workpiece B is loaded onto the turretIII at position I. Following this operation, turret 10 is again indexed,approximately 90, and the first-mentioned workpiece is moved to theposition IV. At this position, if necessary, auxiliary quenching devicefurther quenches the surface of the workpiece. Then, the unloadingdevice 18 removes the workpiece from the turret and moves it into thequench tank 22 for reducing the temperature of the workpiece. Theunloading device I8 places the workpiece B onto the inclined conveyor 24where it is conveyed from the tank 22 to an appropriate repository. Atthis same time, another workpiece B is loaded onto the turret 10 by thedevice I2. As it can be seen, after each index of the turret 10, aworkpiece is loaded and unloaded from the turret. Consequently, thetotal time for providing one hardened axle shaft is approximately thelongest time of the operations performed at the circumferentially spacedpositions I, II, III, and IV plus the time on one turret index. Byproviding the auxiliary quench 20, the cycle time of apparatus A isprimarily determined by about one half of the quenching time which meansthat an axle shaft is hardened in the time required to quench a heatedworkpiece at position Ill, plus the time for indexing the turret I0through one step. This is an improvement over prior devices wherein theloading and unloading time was accumulated to the heating and quenchingtime to provide a substantially increased apparatus cycle. Also, inthose prior devices, the loading and unloading time was critical whereasin the present apparatus these two operations require less time than theheating cycle; therefore, they can be performed more convenientlywithout reducing the production rate through the apparatus A. This is asubstantial advantage over prior axle shaft hardening devices now beingused.

CONVEYING AND WORKPIECE ENGAGING MECHANISM As best shown in FIGS. 1 and2, the conveying and workpiece engaging mechanism 10 which is basicallyin the form of a turret, includes central drive shaft 41 having anenlarged center portion and rotatably mounted in spaced journal blocks42, 44. To index this turret between the four positions, I, II, III, andIV, shown in FIG. 2, there is provided an indexing mechanism 45 whichmay take a variety of structural forms; however, in accordance with theillustrated embodiment of the present invention, this indexing meansincludes a motor 46 connected to a gear box, clutch and brake mechanism48 by a chain 50. Hydraulic coupling 52 provides a swivel connection forintroducing the necessary hydraulic lines into the mechanism 48 forcausing the mechanism to index, as previously described, by engagingclutches and brakes or similar devices within the mechanism. The detailsof mechanism 48 may take a variety of forms and for simplicity thesewell known devices have been omitted. Forming the remaining basicstructural elements of the turret 10 are spaced apart circular supportplates 60, 62. Onto these support plates there are attached four equallyspaced workpiece engaging mechanisms, each including a tailstock 70 anda flange clamp 72. Since all of these mechanisms are substantiallyidentical in structure and function, only one will be described indetail, and this description will apply equally to the other tailstocltsand flange clamps.

Referring now to tailstock 70, as best shown in FIG. I, there isprovided mounting flanges 80, 82 for securing the tailstock onto theplate 60. A reciprocally mounted center 84 having a rearwardly extendingoperating shaft 85 is slidably received within a stationary guide 86formed integrally with flange 82. Center 84 receives a spring loadedworkpiece engaging center 88 for holding the workpieces B along theirgenerally longitudinally extending axes. To reciprocate center 84, thereis provided an operating cylinder 90 having a control rod 92 which is,in turn, connected by a bracket 94 with the operating shaft 85 of center84. This bracket carries a cam plate 96 which coacts with spacedelectrical switches I00, 102 for limiting the forward and reversemovement of the center 84 and the spring loaded center 88. The positionof the switches may be adjusted to compensate for various sizedworkpieces. The electrical control circuit into which these switches areincorporated has been omitted for simplicity, since it is not necessaryto describe the preferred embodiment of the present invention.

Referring now more particularly to FIG. 3, the flange clamp 72 employs amounting plate IIO and a housing I12 secured onto support plate 62 bycircumferentially spaced bolts I14. At the outboard end of housing 112there is provided a motor mounting plate [I6 for a purpose to behereinafter described. Axially spaced bearings I20, I22 are providedwithin the housing I12 for rotatably securing a hollow shaft I24 ontowhich is connected a driven gear by a gear nut 132. To rotate gear 130there is provided a driven gear I34 connected to the output shaft of ahydraulic motor I36 secured onto the previously mentioned motor mountingplate I16. As the motor is rotated, this drives hollow shaft I24 whichis connected by a sliding key coupling I40 with a drive shaft 142secured onto the sliding coupling 140. This drive shaft forms the mainsupport structure for the flange clamp 72. On the left end of shaft 142,as viewed in FIG. 3, there is provided a clamp housing 150. At the otherend, there is provided a collar 152 for a purpose to be hereinafterdescribed. Adjacent this same end of shaft I42, the illustratedembodiment of the present invention, includes a clamp control mechanismI54 including a hollow shaft I60 extending toward the housing 150, apiston 162, a release cavity I64, a clamping spring I66 and a hydraulicinlet 168. When fluid is exhausted from cavity 164, components assumethe position illustrated in FIG. 3. When hydraulic fluid under pressureis introduced into the cavity I64, piston 162 compresses spring I66 andmoves hollow shaft I60 to the left for unclamping the flange 38 of theworkpiece B, as will be described.

Referring now more particularly to the actual clamping structure offlange clamp 72, there is provided a clamp actuating spider secured ontothe extreme end of hollow shaft 160. A plurality of circumferentiallyspaced arms I72 form the actual clamping element of the flange clamp.Referring more particularly to these arms, as illustrated in thepreferred embodiment, they each incorporate a clamping finger 174, afixed pivot pin 176, a slot 178 and a spider sliding pin 1%. When thepiston 162 is in the position shown in FIG. 3, the arms I72 are pivotedinto engagement with the flange 38 for clamping the flange against asupport and locating ring I90. When hydraulic fluid is introduced intocavity I64, piston 162 moves forward which forces pin 180 in slot I78.This rotates the fingers 174 of the arms 172 away from the flange 38.

To locate the workpiece B within the flange clamp 72, there is provideda spring loaded center 192 having sliding bearings I94, I96 and aloading spring I98. By this arrangement, the center 192 is biasedoutward to provide the centering function during the clamping of theflange onto the ring 190.

To load and unload workpieces within turret I0, it is advisable to shiftthe flange clamp housing 150 away from the workpiece receiving area. Toaccomplish this function, various arrangements could be employed;however, in accordance with the preferred embodiment of the presentinvention, this function is accomplished by a shift lever 200 pivotallymounted onto a mounting plate 202 surrounding shaft 41. A cylinder 204secured onto bracket 206 may be actuated to pivot the lever 200 awayfrom plate 62 which, in turn, moves collar 152 to the right, as shown inFIG. 3, for retracting the clamp hous ing 150. When this has been done,the workpiece may be loaded transversely into the turret in a manner tobe described later. A switch rod 210 is connected onto the lever 200 tomove a switch operator 212 between spaced control switches 214, 216.These switches limit the movement of the lever, and thus the housing 150by an appropriate electrical circuit, not illustrated.

The above description of the flange clamp '72 contains a description ofits operation. To summarize this operation, initially the lever 200 isshifted clockwise, as viewed in FIG. 3, which retracts the housing 150.Also, fluid is introduced into cavity 164 which opens the arms 172.Thereafter a workpiece B is located in front of the flange clamp, and alever 200 is moved counterclockwise. This engages the spring loadedcenter 192 against the center in the end of the workpiece to locate theworkpiece. Thereafter, hydraulic pressure is released from cavity 164 sothat spring 166 drives the arms 172 into clamping engagement with flange38. This clamps the flange 38 against ring 190. This operation, taken inconjunc tion with the operation of the tailstock 70 locates theworkpiece within the turret 10. When the workpiece is to be rotated,motor 136 is actuated by an appropriate hydraulic force to rotate gear134 and, thus, gear 130. In this manner, hollow shaft 124 is rotated todrive the housing 150 in a rotary direction. The center 84 is rotatablyreceived within a stationary guide 86 so that it will not interfere withthe rotational movement of the workpiece as caused by the motor 136. Thepurpose of rotating the workpiece at various locations, i.e., positions11, III and IV, will be hereinafter described.

LOADING DEVICE Referring now more particularly to FIGS. 1 and 2, theloading device 12 includes side plates 220, 222 which rotatably mount abar 224 in bearings 226, 228. workpiece receiving elements 230, 232, aresecured for sliding movement on the bar 224. Since these elements aresubstantially identical, only one will be described, and thisdescription will apply equally to the other such element. Element 230includes a cradle 234 for supporting an axle shaft or workpiece B. Asliding key 236 al lows the element 230 to reciprocate on bar 224without allowing rotational movement with respect thereto. Two threadedadjusting rods 240, 242 are threadably received within elements 230,232, respectively. These rods are also rotatably mounted in blocks 244,246 so that they cannot move axially. Ends 250 of these rods are adaptedfor receiving a wrench so that these rods may be rotated to adjust theposition of each element 230, 232 on bar 224. In this manner, workpiecesof different lengths can be accommodated in this loading device. After aworkpiece has been positioned within the two cradles 234, a cylinder 260having a reciprocating rod 262 pivots a crank 264 secured onto bar 224.The workpiece is then moved from the phantom line position to the solidline position in FIG. 2. A workpiece is manually placed upon the cradlesafter the workpiece receiving centers have been retracted and moved intothe loading position. Thereafter, the tailstock and flange clamp atposition I are actuated to grip the workpiece for subsequent movement bythe turret 10. Of course, other arrangements could be utilized forloading the workpiece into the position I of the turret 10.

INDUCTION HEATING DEVICE Induction heating device 14, best shown inFIGS. 2 and 4, includes a single tum inductor 280 for heating thecomplete length of the workpiece B. This inductor includes parallel sidelegs 282, 284 connected by cross legs 286, 288, at the respective ends.In order to direct high frequency electrical current into the inductor,there are provided spaced leads 290, 292 which may be tapped into leg284 at any position along its length. An appropriate supply of highfrequency electrical current is used which supply may take a variety offorms, schematically illustrated as generator 294. This power supply islocated within a case 296 supported upon a movable plate 300. Below themovable plate is a stationary or fixed plate 302 on which the movableplate may rest when it is lowered. To guide the vertical movement ofcase 296 there is provided guide pins 304, only one of which is shown,joumaled within bushing 306. A lower cylinder 308 having a ram 310 isconnected onto the movable plate 300 by a clevice 312 and a dependingarm 314. As illustrated in FIG. 5, the legs 282, 284 are spaced aroundthe circumference of the workpiece B an angular distance ofapproximately I20". In this manner, less upward movement is necessaryfor the inductor by the ram 310 when the workpiece is being moved intoand away from the position II.

In operation, after a workpiece has been loaded into turret 10 atposition I the ram 310 lifts case 296 which shifts the inductor 280 fromthe path of movement of the workpiece while travelling from position Ito position II in a direction generally transverse to the axis of theworkpiece. Thereafter, cylinder 308 lowers the case 296 which brings theinductor 280 into close spacing with respect to the entire workpiecesurface. At that time, motor 136 is actuated to rotate the workpiecewith respect to the inductor and the generator 294 introduces currentflow through the inductor. In this manner, the outer surface of theworkpiece B is inductively heated for subsequent quench hardening. Itwill be noted, in FIG. 4, that the legs 282, 284 are appropriatelycontoured to provide optimum magnetic coupling between the workpiece andthe conductors. In addition, U-shaped larninations 320 are positionedover the end leg 288 for directing and concentrating the flux fieldadjacent the fillet between the cylindrical portion 46 of the workpieceand the flange 38 of the workpiece. Other appropriate changes could bemade in the inductor without departing from the intended scope of thisinvention. For instance, further contouring of the legs 282, 284 couldbe used and iron laminations could be employed throughout the totallength of the conductors forming the inductor to control and direct theflux field being used to heat the outer surface of the workpiece B.

After the heating cycle, the case 296, and inductor 280, are againlifted by the ram 310 so that the workpiece will not contact theinductor as it is being indexed from the heating position I] to thequenching position 11].

QUENCHING DEVICE Referring now more particularly to FIGS. 2 and 6, thequenching device 16 at position III includes an elongated generallyarcuately shaped quench body 330 having an internal quench liquidpassage 332, a quenching liquid inlet 334 and quenching fluid outlets orapertures 336 on an elongated arcuate surface. The quench body 330 issecured onto a sup port 340 secured to sliding pins 342, only one ofwhich is shown. These pins are received in bushings 344 mounted uponframe 345. A cylinder 346 actuates a ram 348 to reciprocate the support340 for moving the quench body into and out of its quenching position.

Before the turret 10 is indexed, cylinder 346 shifts the quench body 330into the phantom line position shown in FIG. 2. After the workpiece Bhas been indexed into position III, cylinder 346 is again actuated tolift the quench body 330 into the solid line position shown in FIG. 2.Thereafter, by an ap propriate control mechanism, quenching liquid isdirected from the apertures onto the cylindrical body portion 34 ofworkpiece B. During this quenching operation, motor 136 is actuated torotate the workpiece for uniform quenching of the previously inductivelyheated outer surface. After an appropriate quenching time, the quenchingliquid flow is stopped and cylinder 346 shifts the quench body 330 intoits retracted position so that the workpiece can be indexed fromposition III to position IV.

UNLOADING DEVICE Referring now to FIGS. l and 2, unloading device 18 atposition IV includes a pair of spaced unloading arms 350, 352 eachhaving a cradle 353 for supporting a workpiece B. These arms areslidably secured onto shaft 354 by sliding keys 355. Rotation of theshaft is permitted through the use of journals 356, 358 within plates220, 222, respectively. As in the case of the loading device, threadedadjusting rods 360, 362 are provided for adjusting the spacing betweenthe location of the unloading arms 350, 352. To pivot the arms 350, 352from the phantom line position to the solid line position shown in FIG.2, there is provided a cylinder 364 which operates a ram 366 connectedonto a crank 368. The crank pivots the shaft 354 for moving theunloading arms.

In operation. after the workpiece is indexed by turret to position IV,the arms 350, 352 are pivoted upwardly to receive the workpiece incradles 353. At that time, appropriate controls are actuated for liftingarms 172 out of contact with flange 38, shifting the tailstock 70 awayfrom the workpiece, and shifting the flange clamp 72 away from theworkpiece. This leaves the workpiece supported by the arms 350, 352.Thereafter, the arms are pivoted downwardly to deposit the workpieceonto conveyor 24 for removal. Details of the conveyor will be describedlater.

AUXILIARY OUENCHING DEVICE In some instances, the quenching cycle atposition III, for optimum results, will require more time than theheating operation at position I]. Instead of increasing the cycle of theturret indexing, it is anticipated that an auxiliary quenching device 20will be provided at position IV. This quenching device includes anarcuate quench body 370 extending over approximately 90 of the workpieceB. It is on the opposite side of position IV from the workpiece B sothat it does not form interference with this workpiece as it is beingindexed into position IV. Consequently, the auxiliary quenching devicemay be fixed on a bracket 37]. Within the quench body 370 there isprovided internal quench liquid passage 372 and a quench liquid inlet374. In the arcuate shaped surface facing the workpiece B there areprovided a number of apertures 376 through which the quench liquid ispassed onto the surface of the workpiece B. This provides an auxiliary,or subsequent, quenching to augment the quenching effected at III. Whenfliis auxiliary quenching is used, workpiece B is not unloaded from theturret when the workpiece first moves into position IV. Also, theworkpiece is rotated in this position during the quenching operation toprovide a uniform auxiliary quench. It is anticipated that thisauxiliary quench need not be used if the main quench at position I" issufficient for proper quench hardening of the workpiece.

INCLINED CONVEYOR Referring now to FIG. 2, the inclined conveyor 24mounted in tank 22 is positioned below the arms 350, 352 and includes,in the illustrated embodiment, spaced sprockets 380, 382 connected by acontinuous chain 384. workpiece receiving brackets 386 are spaced alongthe chain to receive and remove workpieces from the arms 350, 352 whenthey are pivoted into the solid line position shown in FIG. 2. The motor390 drives a chain 392 which, in turn, actuates a gear box 394 forrotating the sprockets 382. This drives the inclined conveyor to removethe workpieces from the unloading device while in tank 22 and convey theworkpieces to an appropriate position. Quenching liquid within the tank22 is at a level so that the workpieces are submerged before beingremoved from the unloading arms. This provides the final cooling for theworkpieces before they are discharged from apparatus A.

OPERATION The operation of a device A has been described in connectionwith the various components forming this apparatus; however, it shouldbe appreciated that as the turret indexes a given workpiece from oneposition to the next, additional workpieces are being loaded onto theturret at position I. Consequently, four workpieces may be on the turretat one time. A cycle for a single workpiece is then determined by theindexing time and the longest operating cycle within the apparatus A.Generally this is the quenching cycle at position III; however, it canbe the heating cycle at position I]. When the quenching cycle is longer,the auxiliary quenching device 20 can divide the quenching time betweenthe positions III and IV.

In practice the high frequency current used in the heating cycle is3,000 cycles per second. With the workpiece rotated at revolutions perminute and a power input of approximately 450 Kilowatts the heating timefor a one inch diameter axle shaft is approximately yl2 seconds.Quenching time is approximately 25 seconds, about l2-l3 seconds atposition III and about the same at position IV. Auxiliary quenchingdevice 20 is continuous; therefore, quenching is effected as soon as theworkpiece approaches position IV. This increases the quench time atposition IV. Consequently, the quenching time is controlling on theoperating rate. The processing cycle, in this instance, would beapproximately l3 seconds, plus indexing time of about three seconds. Theauxiliary quenching device, in this example, is utilized forapproximately 12-13 seconds or about the same time as the heating cycle.This is a substantial improvement over the cycle time required for axleshaft hardening machines now commonly used.

OTHER EMBODIMENTS As previously mentioned, the leg 284 of inductor 280can be tapped at various positions. This is illustrated in FIG. 8wherein inductor 400 has parallel legs 402, 404 and connecting legs 406,408. This inductor is used to heat a workpiece 410 having no end flange.Leg 402 is tapped at one end by two input leads 412, 414 connectedacross a power source M6.

The preferred embodiment of the present invention involves the use offour separate positions for turret 10. However, various othercombinations of turret positions can be employed.

In FIG. 9, turret 10' has three positions, i.e., I [1,, and III Atposition I, a workpiece B is loaded onto the turret. At position II aninductor 420 is moved into the heating position, and the workpiece B isinductively heated. A quench unit 422 is shifted into the illustratedlocation in position III, for quenching the workpiece. At this sameposition, the workpiece is unloaded from turret I0.

FIG. 10 shows still another embodiment of the invention wherein fivepositions (1,, II,, III,,, IV, and V are employed. In this instance,workpiece H" is loaded onto turret 10" at position I At position II,,,the workpiece is heated by an inductor 430 shifted into heatingrelationship with the workpiece. Positions Ill, and IV, are used toquench the workpiece by quench units 432, 434, respectively. Anauxiliary quenching device 436 further quenches the workpiece atposition V before the workpiece is unloaded at this same position.

Referring now to FIG. 1 l, turret 10" employs six separate positions, lvl At position I workpiece B' is loaded onto the turret. The workpieceis then preheated in position Il by a shiftable inductor 440 and finallyheated by shiftable inductor 442 at position III Quenching devices 444,446 are shifted into quenching relationship with the workpiece atpositions W and V for quenching the workpiece. At position VI theworkpiece is unloaded.

Other similar modifications can be made in the invention to accomplishproper induction heating and quench hardening of the workpieces.

We claim:

1. An apparatus for inductively heating and quench hardening anelongated workpiece having spaced ends and an elongated generallycylindrical body with a longitudinally extending axis, said apparatuscomprising: a rotary indexing means for moving a workpiece successivelyin a generally circular path transverse to said axis from a firstposition, to a second position, to a third position, to a fourthposition; loading means at said first position for loading a workpieceonto said indexing means; heating means at said second position forinductively heating said cylindrical body, said heating means comprisingan inductor having a single turn conductor with two generally parallelside legs extending generally parallel to said axis and spaced slightlyfrom said elongated body when said inductor is in a heating position andend legs electrically connecting said side legs and extending arcuatelyaround said body, said side legs extending generally the complete lengthof said cylindrical body, means for rotating said workpiece about saidaxis, and means for creating a high frequency current to flow throughsaid conductor to heat said body; quenching means at said thirdposition, said quenching means comprising a quench body having a lengthgenerally corresponding to the length of said side conductors, agenerally arcuate surface extending the length of the said quench body,apertures in said surface to allow flow of quench liquid therethrough,means for forcing quenching liquid through said apertures and onto saidcylindrical body and means for rotating said workpiece about said axis,unloading means at said fourth position for unloading said workpiecefrom said indexing means; means for actuating said indexing means formoving a workpiece successively from said first position, to said secondposition, to said third position and to said fourth position; means forshifting said inductor away from said path when said actuating meansactuates said indexing means; means for shifiing said quenching meansand from said path when said actuating means actuates said indexingmeans; means for shifting said inductor into said heating position whensaid indexing means is stopped; and, means for shifting said quenchingmeans into an operative position when said indexing means is stoppedwhereby said workpiece may be moved between said positions withoutinterference from said inductor and said quenching means.

2. An apparatus as defined in claim 1 including a second quenching meansat said fourth position for further quenching of said cylindrical body.

3. An apparatus as defined in claim I wherein said side conductors arespaced less than 180 from each other with respect to said cylindricalsurface.

4. An apparatus for inductively heating and quench hardening anelongated workpiece having spaced ends and an elongated generallycylindrical body with a longitudinally extending axis, said apparatuscomprising: conveyor means for conveying said workpiece along a pathgenerally transverse to said axis; means for stopping movement of saidworkpiece when it reaches a selected position in said path; heatingmeans at said selected position for inductively heating said cylindricalbody, said heating means comprising an inductor having a single turnconductor with two generally parallel side legs extending generallyparallel to said axis and spaced slightly from said elongated body whensaid workpiece is at said selected position and end legs electricallyconnecting said side legs, said side legs extending generally thecomplete length of said cylindrical body, means for rotating saidworkpiece about said axis while at said selected position, and means forcreating a high frequency current to flow through said conductor to heatsaid body; said inductor having a first fixed heating position with saidside legs closely adjacent said body and extending into the path ofmovement of said workpiece and a second retracted position with saidside legs spaced from the path of movement of said workpiece, means forshifting said inductor into said retracted position as said conveyormeans causes said workpiece to approach and depart from said selectedposition and means for shifting said inductor into said fixed heatingposition when said workpiece is stopped in said selected position bysaid stopping means; and, means for fluenching said workpiece afteri isinductively heated by sai heating means, said quenching means comprisinga generally U-shaped quench body extending substantially the completelength of said cylindrical body and surrounding said cylindrical bodyduring quenching.

5. An apparatus for inductively heating and quench hardening anelongated workpiece having spaced ends and an elongated generallycylindrical body with a longitudinal axis, said apparatus comprisingconveying means for conveying a succession of said workpieces betweenfirst, second, third and fourth positions along a path generallytransverse to the axis of said workpieces, means at said first positionfor loading workpieces onto said conveyor means; means at said secondposition for inductively heating the cylindrical bodies of saidworkpieces, said heating means including a single turn inductor with agenerally arcuate side profile, means for locating said side profileadjacent said cylindrical bodies of said work pieces and spacedtherefrom, said inductor having a length generally corresponding to thelength of said cylindrical bodies and means for rotating said workpiecesat said second position, means at said third position for quenching saidheated cylindrical bodies, said quenching means including means fordirecting a quenching liquid against said bodies and means for rotatingsaid workpieces at said third position; second means at said fourthposition for quenching said heated cylindrical bodies, said secondquenching means including means for directing a quenching liquid againstsaid bodies and means for rotating said workpieces at said fourthposition; and means for removing workpieces from said con- VBYOI means.

min-vi man

1. An apparatus for inductively heating and quench hardening anelongated workpiece having spaced ends and an elongated generallycylindrical body with a longitudinally extending axis, said apparatuscomprising: a rotary indexing means for moving a workpiece successivelyin a generally circular path transverse to said axis from a firstposition, to a second position, to a third position, to a fourthposition; loading means at said first position for loading a workpieceonto said indexing means; heating means at said second position forinductively heating said cylindrical body, said heating means comprisingan inductor having a single turn conductor with two generally parallelside legs extending generally parallel to said axis and spaced slightlyfrom said elongated body when said inductor is in a heating position andend legs electrically connecting said side legs and extending arcuatelyaround said body, said side legs extending generally the complete lengthof said cylindrical body, means for rotating said workpiece about saidaxis, and means for creating a high frequency current to flow throughsaid conductor to heat said body; quenching means at said thirdposition, said quenching means comprising a quench body having a lengthgenerally corresponding to the lengtH of said side conductors, agenerally arcuate surface extending the length of the said quench body,apertures in said surface to allow flow of quench liquid therethrough,means for forcing quenching liquid through said apertures and onto saidcylindrical body and means for rotating said workpiece about said axis;unloading means at said fourth position for unloading said workpiecefrom said indexing means; means for actuating said indexing means formoving a workpiece successively from said first position, to said secondposition, to said third position and to said fourth position; means forshifting said inductor away from said path when said actuating meansactuates said indexing means; means for shifting said quenching meansaway from said path when said actuating means actuates said indexingmeans; means for shifting said inductor into said heating position whensaid indexing means is stopped; and, means for shifting said quenchingmeans into an operative position when said indexing means is stoppedwhereby said workpiece may be moved between said positions withoutinterference from said inductor and said quenching means.
 2. Anapparatus as defined in claim 1 including a second quenching means atsaid fourth position for further quenching of said cylindrical body. 3.An apparatus as defined in claim 1 wherein said side conductors arespaced less than 180* from each other with respect to said cylindricalsurface.
 4. An apparatus for inductively heating and quench hardening anelongated workpiece having spaced ends and an elongated generallycylindrical body with a longitudinally extending axis, said apparatuscomprising: conveyor means for conveying said workpiece along a pathgenerally transverse to said axis; means for stopping movement of saidworkpiece when it reaches a selected position in said path; heatingmeans at said selected position for inductively heating said cylindricalbody, said heating means comprising an inductor having a single turnconductor with two generally parallel side legs extending generallyparallel to said axis and spaced slightly from said elongated body whensaid workpiece is at said selected position and end legs electricallyconnecting said side legs, said side legs extending generally thecomplete length of said cylindrical body, means for rotating saidworkpiece about said axis while at said selected position, and means forcreating a high frequency current to flow through said conductor to heatsaid body; said inductor having a first fixed heating position with saidside legs closely adjacent said body and extending into the path ofmovement of said workpiece and a second retracted position with saidside legs spaced from the path of movement of said workpiece, means forshifting said inductor into said retracted position as said conveyormeans causes said workpiece to approach and depart from said selectedposition and means for shifting said inductor into said fixed heatingposition when said workpiece is stopped in said selected position bysaid stopping means; and, means for quenching said workpiece after it isinductively heated by said heating means, said quenching meanscomprising a generally U-shaped quench body extending substantially thecomplete length of said cylindrical body and surrounding saidcylindrical body during quenching.
 5. An apparatus for inductivelyheating and quench hardening an elongated workpiece having spaced endsand an elongated generally cylindrical body with a longitudinal axis,said apparatus comprising conveying means for conveying a succession ofsaid workpieces between first, second, third and fourth positions alonga path generally transverse to the axis of said workpieces, means atsaid first position for loading workpieces onto said conveyor means;means at said second position for inductively heating the cylindricalbodies of said workpieces, said heating means including a single turninductor with a generally arcuate side profile, means for locating saidside profile adjacenT said cylindrical bodies of said workpieces andspaced therefrom, said inductor having a length generally correspondingto the length of said cylindrical bodies and means for rotating saidworkpieces at said second position, means at said third position forquenching said heated cylindrical bodies, said quenching means includingmeans for directing a quenching liquid against said bodies and means forrotating said workpieces at said third position; second means at saidfourth position for quenching said heated cylindrical bodies, saidsecond quenching means including means for directing a quenching liquidagainst said bodies and means for rotating said workpieces at saidfourth position; and means for removing workpieces from said conveyormeans.